Hello, I currently have a 2009 double cab 4.0 2wd Trd package. I recently ordered the volant cold air intake and the ram air scoop for better air flow and a few more hp. I wanted to know if adding headers would improve hp+torque? Also If I were to add headers, would if be a smart idea to get an after market exhaust system for better air flow at the rear?

I would recommend picking up the URD Maf cal before getting headers. The volant intake does some screwy things to the MAF accuracy in our trucks. Some trucks are ok, most have A/F readings that hurt performance more then they help.

Tune for that intake, then add headers and a catback, retune, and you will def like the power gains.